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Deciduous trees act as a fire retardant and are often the reason why some houses survive a bushfire when neighbouring houses are burnt. Why do they provide fire protection and how can they be used in rural areas to make summers safer? ![]() The Weekend Australian Feb 21 2009 A former owner of the Crossways Hotel in Marysville, which survived the fire in 2009, Mr Lawrey is advising residents to plant European trees around their houses rather than eucalypts. "European trees saved my house," he said. "The embers that landed in the trees had time to burn out". If they land in eucalypts, they burn immediately. "He said all three commercial buildings left standing in Marysville had European trees nearby. They really cooled the fire down when it reached them" ![]() The benefits of deciduous plants. Deciduous plants are very useful around the home and in public places not only because they add to the ambient beauty but also because they provide cooling shade in the summer and let the sunlight through in the winter. Evergreen trees are unable to provide this shade contrast. In fact Australian natives often do the reverse and let more sunlight through in the summer by turning the flat surface of their leaves away from the sun to reduce transpiration loss. Some natives like eucalypts let in more light by shedding their leaves during the very hot dry periods. Deciduous trees cool the air around them through transpiration. The water held in leaves is released from the stomata as water vapour. A Similar evaporative cooling principle is used in air-conditioners. On a hot day it is possible to feel the temperature drop a few degrees as you walk from the shade of native trees under deciduous trees. I experienced this tangible temperature change recently on a visit to the Adelaide Botanic gardens on a 38 degree day walking beneath a very large London Plane tree. It wasn't a coincidence that many more visitors to the gardens that day were seated under this shady tree than could be seen in the rest of the gardens. Additional benefits of a deciduous trees and vines are fruit & nuts; timber for craft, furniture, and building; firewood, attractive flowers and autumn foliage; shade; privacy screening and as mentioned before they let in the winter sunlight which can make a cold room warmer and dry a boggy track. ![]() How deciduous plants provide protection from bushfires. Deciduous plants are fire retarding because they have high moisture content in their leaves without the flammable oils. They can provide excellent fire protection in four ways. 1. By shielding buildings from the damaging effects of a fire's radiant heat. A vegetation screen between a building and an oncoming fire can prevent windows shattering, plastics melting and timbers buckling by reducing the radiant heat emanating from the fire. Radiant heat is short and intense because a bushfire front takes only 30 - 40 seconds to pass through. In extreme fire conditions a house has to withstand temperatures of up to 1200 degrees for about two minutes if it is exposed to the full un-shielded intensity of the radiant heat. Native trees and shrubs will also shield a house from radiant heat. ![]() 2. By catching flying glowing embers before they reach the home. It's not uncommon to hear stories about people who stayed to save their homes and later celebrated with friends at the pub only to return to a smouldering ruin. The cause of this enormous disappointment and personal tragedy are the airborne embers of burning leaves and bark that cause spot fires ahead of a fire-front and continue to fall after a fire has passed. Many airborne embers become caught up in the foliage of surrounding trees. If they become caught in deciduous trees they're no longer likely to be a threat. 3. By 'snuffing' out the embers they catch. The water filled leaves of deciduous trees will cool and extinguish glowing embers in the same way that water puts out a fire. The leaves on the side nearest to the fire-front will be scorched as they take the heat out of the embers but they won't ignite and add to the intensity of the fire. A eucalypt or a pine could accelerate the fire and burn because they releasing volatile oils which can spontaneously ignite at temperatures above 60 degrees. ![]() 4. The leaf litter isn't flammable and breaks down rapidly to humus, improving the soils ability to hold moisture. Have you ever noticed the smouldering heaps of raked deciduous leaves in the late Autumn? Some over zealous gardeners try to burn them when its much easier to turn them into compost. They are difficult to burn and this feature will stop a fire from spreading. This was observed after the devastating Western Australian fires of 2009 by a firefighter defending a house at Ferndale. "Every ember that fell on the side of the house that was planted with Blue Gums started a fire in the fallen gum leaves. Every ember that fell on the other side, amongst the poplar leaves, just petered out. There was a 100 percent difference. ![]() Where to plant for fire protection. The key fire sectors are north, north west, west and south west. These are the directions that a fire will come from and also the sides of a property best planted with deciduous trees or vines. Bad fire days are always associated with strong northerly or north westerly winds. North winds are warm in summer as they blow across the northern deserts before they reach the southern states. These warmed gusty winds can strip the moisture from leaves and cause less hardy plants to wilt. Wind directions can change. A cool change is always very welcome when it brings relief from extreme heat, but it can turn a fire to the east. If a fire is coming from the north with a narrow front and is turned toward the east by a westerly change, the long eastern edge of the fire becomes the new and much longer fire front. To protect your home against all these possibilities imagine a semicircular zone from the south-west extending to the north and plant this zone with deciduous plants to guard against the unpredictable nature of fire. Choose trees appropriate to the size of the space available because large deciduous trees can dry out garden beds and cause structural damage if planted too close to a building. ![]() What deciduous plants are suitable for your country property. When choosing suitable plants you will have more success if you factor in your annual rainfall, aspect (south & east facing positions and slopes are cooler than north & west facing), drainage and soil type. This knowledge is critical and can make the difference between success and failure whether you are planting hardy natives or exotic deciduous trees. This knowledge is also very useful when you visit your local nursery. Generally in dry areas drought tolerant plants will cope with a long dry spell and hold on to their leaf moisture in the dry months. This is a very important feature if they are to function as a fire shield. I have added some potential uses and cautionary notes in brackets below as an alert to help your choice and avoid future regrets. Always check the eventual size of the trees you're planting and keep them at least 1.5 times their mature height from any structures with foundations. Very large trees like the Beeches, some larger maple species, Weeping Willow and London Plane can cause structural damage and their roots can lift paved areas. On the brighter side, an avenue of London Plane trees planted in the fire sector will provide a very effective fire shield from 40 meters away from a homestead. The following genera of deciduous trees prefer moist soils. They are unsuitable as fire shields in dry climates unless they are in a moist gully or well irrigated: Willows (an environmental weed on waterways, one species used traditionally to make cricket bats). Poplars (buy non suckering cultivars, valuable timber). Most oaks (valuable timber, acorns are edible if the bitter tannins are removed by repeated boiling). Maples (valuable timber). Birches (valuable timber). Beech (valuable timber, edible nuts). The following genera of deciduous trees are hardy and tolerate very dry conditions: Ash (Desert Ash is very hardy but potentially a weed, grafted cultivars like the Claret Ash are not weedy, valuable timber). Plane (valuable timber, the roots are deep, invasive and potentially damaging). Hawthorn (spread by birds and can become an environmental weed), Black Locust (boat building timber, firewood, will sucker). Honey Locust (valuable hardwood) ![]() The following common fruit and nut varieties will cope well with long dry periods when established: For a good crop in dryer locations drip irrigation is recommended. Quince (will sucker), pomegranate, plum, persimmon, pecan, pear, mulberry, fig (will sucker), apricot and almond. Apple, peach, nectarine are less drought tolerant but will still survive without irrigation if 'the dry' is not too prolonged. ![]() Walnut (Black Walnut provides valuable timber), hazelnut, chestnut and cherry definitely need moist soil with good drainage and prefer cooler summers Ornamental pears and ornamental prunus are a very useful medium sized trees that will cope with drought and poor drainage. The prunus genus which includes almond, apricot and plum are tough and adaptable to most soils particularly if they are grafted onto plum rootstock. I have included this link to 'The ultimate guide to fruit & ornamental trees' published by Flemmings. It should answer any questions you may have about the suitability of different trees. Flemmings are a well known nursery dynasty that have researched and published this excellent guide to trees that they sell through retail outlets. There are cheaper wholesalers of deciduous and fruit trees, so it is definitely worth shopping around. Ornamental and fruiting grape vines are also very hardy and can be used as a trellised fire shield. Deciduous trees provide many benefits around human settlements but reducing the fire risk is arguably a most critical asset that should be considered for every rural home. Planting back the indigenous and native vegetation in rural and urban areas is essential to protect our indigenous flora and fauna and to restore the resilience of the natural environment to change, but it would be foolish to ignore the advantages that deciduous plants offer to human safety in the advent of a serious fire. You might also like these articles on bushfire safety by Stephen Murphy; ![]() ![]() ![]()
60 Comments
Valerie Hathaway
26/11/2017 09:52:41 am
I have a love of Ribinia deciduous trees & would love to create an avenue of them on my daughter & son inlaws property at Woodstock NSW. I found the article very informative, thankyou so much.
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locust
26/11/2017 11:07:15 am
Hi Valerie
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This was a very Interesting read. I am Surprised that towns in rural/bushfire prone areas do not heed this advice (One only needs to look at the 2009 VIC bushfires to see). I think this valuable information should be widely distributed so that people can plant all around their properties, deciduous trees to protect against the devasting fires. I Think that this article needs to be shared and distributed so that people can be educated about the benefits of planting deciduous european trees on their properties to protect against bushfires. What a fascinating read this was. I will share this info with many people to come. Thank you for infroming me about this
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Steve
5/2/2019 08:33:05 am
Thanks Stephen for your encouraging comments. I agree that it does seem an obvious strategy in bush fire prone areas. There is plenty of anecdotal evidence of houses that survived fires to support the logical benefits of planting deciduous trees around rural homes.
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bronwyn
18/2/2019 03:20:23 am
Thank you for your article - 10 years after losing our home on Black Saturday l too am about too share my experience of what l witnessed after coming "home" .
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Steve
19/2/2019 02:11:58 pm
Hi Bronwyn,
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Justine
25/2/2019 01:23:24 pm
Thank you for your excellent and informative article. I am curious about one issue; the planning permit conditions that state that tree canopies within the defencible area should be not connected.
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Steve
2/3/2019 01:48:55 pm
Hi Justine,
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Caroline Johnson
23/12/2019 06:06:40 pm
We have giant elm trees all around our old cottage. you know what...if the floor cracks, I dont mind cos the trees will protect us in a fire as the Fire Service says, and i love them on 40 degree days as they keep us cool. SO WHAT if your slab cracks. its not the end of the world. I do not agree with this 1.5 x height of tree from house rule. Those plantings will not keep your home cool or improve the amenity of your verandah. Oour new extension was desighned on posts to not disturb the tree roots and we love living under them. So what if a bough falls on the roof. Insurance covers it and they give us too much money for it. with climate change we need to plant way more trees.
Sue
5/3/2019 01:46:21 pm
This sounds like very sensible advice. Do you have any recommendations about how to keep newly planted deciduous (European) or Australian native rainforest trees alive through the increasingly brutal hot, dry summers of climate change? We have tried several times to implement your ideas, but our trees just seem to fry during the summer - and the only things we can keep alive are native i.e.. flammable trees and shrubs.
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Steve
5/3/2019 06:48:41 pm
Hi Sue,
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Adam
1/3/2020 08:48:56 am
Have you tried deciduous Mediterraen trees that are more heat tolerant? Or even the few australian decicduous trees like Tona or Melia?
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Steve
8/3/2020 12:19:50 pm
Hi Adam,
rick
6/3/2019 09:21:04 am
I googled "Marysville bushfires" and followed a link to this site. Very interesting reading. I agree, from experience, with the shade and cooling benefits of deciduous European trees. I can't comment on the bushfire retardant benefits, but it seems to make sense.
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Steve
13/3/2019 06:18:08 pm
Thanks for your thoughtful comments and interesting observations rick.
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26/8/2019 12:55:48 am
Hi Steve,
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Steve
26/8/2019 12:02:13 pm
Hi Peta, 18/3/2019 06:55:39 pm
If you lead a busy lifestyle or want instant results with little or no maintenance, consider lifelike artificial Garden screens Perth to add nature to your home.
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1/4/2019 11:55:46 pm
Hi stephen,
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Bronwyn
12/4/2019 09:44:06 am
Hello Stephen,
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Bronwyn
12/4/2019 10:27:08 am
Sorry my little girl pressed the submit button before l finished my comment...
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Steve
15/4/2019 12:54:00 pm
Hi Bronwyn,
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Peter
14/1/2020 05:44:51 pm
This sort of tree planting does not work in most situations .My brothers orchard of fruit and nut trees was turned to ash along with his house and sheds and all the trees on his farm .A gully running across the back of this house may have caused a draught way from the house .Or just sheer luck .I think its very wrong to suggest planting any trees close to a house .30 years CFS experience tells me the only thing to save a house is clear ground or very low moisture filled plants ... 4/10/2019 03:34:39 am
If they land in eucalypts, they burn immediately. "He said all three commercial buildings left standing in Marysville had European trees nearby. They really cooled the fire down when it reached them
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Steve
8/10/2019 07:49:50 am
Hi Ingilis
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Steve
16/12/2019 09:54:28 pm
Hi great article thanks!
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Steve
18/12/2019 04:00:35 pm
Hi Steve,
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Ron
29/12/2019 07:41:59 pm
Hi.
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Steve
31/12/2019 02:33:44 pm
Hi Ron,
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KarinP
31/12/2019 11:46:08 am
Great, timely read
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Steve
31/12/2019 02:46:35 pm
Thanks Karin,
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Jane
9/1/2020 12:26:33 am
What an excellent, informative article thank you and it makes so much sense. Like many practical things I cannot understand why 'the powers that be' cannot listen & incorporate these simple systems into how we can best protect this country and ALL who live in it. The best that many of us can do is to do the best we can in our own worlds & every bit counts. This includes sharing this and other factually based information far & wide, surprisingly I only came across this article/way of thinking today.
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Steve
9/1/2020 02:38:54 pm
Hi Jane,
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Ruth Kessler
13/1/2020 12:30:28 pm
I started planting my 5 acres over 30 years ago. I retained natural bush and trees and placed the deciduous trees in an ember catching net around the house half acre. Should also help with radiant heat. I also have about 3 half acres of paddock grass that if not mowen or eaten into the ground will stay green This is not possible in many areas. Being in the Dandenongs [bush fire central] this was a solution I saw work on Ash Wednesday at Mt Macedon. Where the big leafy trees saved many of the old homes. Even a huge Laurel hedge protected a 100 yr old cottage when the rest of the street went up. My assumption was Laurel would be very flammable but in this case seemed not. Have passed your article on.
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Steve
13/1/2020 01:27:44 pm
Hi Ruth,
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Mary
22/1/2020 07:11:50 pm
Hi Steve,
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Steve
23/1/2020 05:34:23 pm
Hi Mary,
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Dinah
26/1/2020 06:30:15 pm
Thank you for the great article Steve, and the site, which I have just discovered today. I look forward to exploring it further. I'm wondering whether you think native deciduous trees such as white cedar would have the same properties in terms of serving as a firebreak. I note the information above on the red cedar - I believe they are of a different family? Also wonder about the semi-deciduous Illawarra flame tree. Thanks.
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Steve
29/1/2020 12:59:30 pm
Thanks Dinah,
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Marilyn
19/2/2020 07:15:19 am
Thanks for your article, Steve. Our home and 3.4 acre garden was destroyed in the NYE bushfires, and the only vegetation which has survived has been the deciduous ornamentals. Sadly, these were not located in a position which could protect our home. To the north, an area which sloped gently then steeply away from the house, we had removed as many of the turpentines and eucalypts as originally permitted and we maintained the ground underneath well, but these trees acted as a catalyst rather than a protective barrier. ( The original Council/ RFS assessment 15 years ago wanted these trees to remain to trap embers). At least now, thanks to their total destruction, we can create the three layered deciduous tree barrier we wanted before! It’s a shame it has taken so long for knowledge to catch up - our initial preference was aesthetic, but in hindsight would also have been intelligent and may have saved our home.
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Steve
21/2/2020 07:32:19 pm
Hi Marilyn,
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Brett
11/6/2020 04:19:09 pm
Hi Steve,
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Steve
22/6/2020 11:54:27 am
Hi Brett,
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laurence anderson
15/6/2020 05:05:38 pm
I have been saying for year that deciduous trees should be the only planting in towns and round houses. In addition, if the 50m either side of highways was planted with deciduous tees the timber would be valuable and fires easier to control. They could also be used as firebreaks; eg in a belt a kilometre wide.
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Steve
22/6/2020 12:10:27 pm
Hi Laurence,
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Randy
19/6/2020 01:48:51 pm
Eucalyptus trees are a major fire hazard in California. At least one fire in Los Angeles was started from a power line sparking directly into a eucalyptus tree, which are not native to North America.
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Steve
22/6/2020 12:20:48 pm
Hi Randy,
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17/7/2020 05:25:14 pm
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Hi Steve thanks for a great article
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Steve
24/8/2020 12:10:46 pm
Hi Kemble,
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1/10/2020 03:58:04 pm
Life always finds its way. It will thrive n grow back more amazing. It will just take time but it will be back beautifully.
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Steve
4/10/2020 10:41:43 am
Thanks Stanley for those positive and uplifting sentiments. Its important to look forward to a future that offers us hope and beauty in nature. The Australian bush has clearly this ability to recover and thrive after adverse events like fire.
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2/10/2020 12:19:57 pm
Your simplicity of presentation is motivating for learning. Please keep it up for your teeming followers.
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Steve
4/10/2020 10:45:48 am
Hi Jake,
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Ken Wild
1/2/2021 06:43:59 pm
Hi Steve,
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Steve
4/2/2021 02:40:10 pm
Thank you for those great comments Ken,
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Glen Walling
25/2/2021 11:39:42 pm
Not at all a new concept. In Bill Mollison's Designers Manual (1988) It discusses this very issue. Like all great ideas and people who come up with them they are either dismissed, ignored or attacked by those with a vested interest or cannot see beyond their own paradigms.
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Steve
26/2/2021 11:57:48 am
I agree absolutely Glen,
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13/12/2021 02:42:58 pm
Sometimes a good idea has to be repeated over and over to get people's attention and sometimes its simply the right idea at the right time. Thank you very much!
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Stephen Murphy is an author, an ecologist and a nurseryman. He has been a designer of natural landscapes for over 30 years. He loves the bush, supports Landcare and is a volunteer helping to conserve local reserves. ![]() |